Complex compounds and their use in olefin polymerization

ABSTRACT

Complexes of the formulae I a to d, 
                 
 
where M is an element of groups 6 to 10 of the Periodic Table of the Elements, preferably Ni, can be used for the polymerization and copolymerization of olefins, for example in suspension polymerization processes, gas-phase polymerization processes, bulk polymerization processes and emulsion polymerization processes.

The present invention relates to complexes of the formulae I a to d,

where the variables are defined as follows:

-   M is an element of groups 6 to 10 of the Periodic Table of the    Elements in the oxidation state +2 to +4,-   Nu is selected from among O, S and N—R⁷;-   R¹ to R⁷ are selected from among hydrogen,    -   C₁-C₈-alkyl, substituted or unsubstituted,    -   C₂-C₈-alkenyl, substituted or unsubstituted, having from one to        4 isolated or conjugated double bonds;    -   C₃-C₁₂-cycloalkyl, substituted or unsubstituted, C₇-C₁₃-aralkyl,    -   C₆-C₁₄-aryl, unsubstituted or substituted by one or more        identical or different substituents selected from among        -   C₁-C₈-alkyl, substituted or unsubstituted,        -   C₃-C₁₂-cycloalkyl,        -   C₇-C₁₃-aralkyl,        -   C₆-C₁₄-aryl,        -   halogen,        -   C₁-C₆-alkoxy, substituted or unsubstituted,        -   C₆-C₁₄-aryloxy,        -   SiR⁸R⁹R¹⁰ and O—SiR⁸R⁹R¹⁰;    -   five- and six-membered nitrogen-containing heteroaryl radicals,        unsubstituted or substituted by one or more identical or        different substituents selected from among        -   C₁-C₈-alkyl, substituted or unsubstituted,        -   C₃-C₁₂-cycloalkyl,        -   C₇-C₁₃-aralkyl,        -   C₆-C₁₄-aryl,        -   halogen,        -   C₁-C₆-alkoxy,        -   C₆-C₁₄-aryloxy,        -   SiR⁸R⁹R¹⁰ and O—SiR⁸R⁹R¹⁰;            where adjacent radicals R¹ to R⁷ may be joined to one            another to form a 5- to 12-membered ring;-   L¹ is an uncharged, organic or inorganic ligand,-   L² is an organic or inorganic anionic ligand, where L¹ and L² may be    joined to one another by one or more covalent bonds,-   z is an integer from 1 to 3,

R⁸ to R¹⁰ are identical or different and are selected from amonghydrogen, C₁-C₈-alkyl, C₃-C₁₂-cycloalkyl, C₇-C₁₃-aralkyl andC₆-C₁₄-aryl.

The present invention also relates to a process for preparing the novelcomplexes from ligands of the formula II,

and a process for the polymerization or copolymerization of olefinsusing a complex of the formula I.

Furthermore, the present invention relates to a process for preparingsupported polymerization catalysts using the novel complex of theformula I, and to a process for the polymerization or copolymerizationof olefins using the novel supported catalysts.

Finally, the present invention relates to a process for the emulsionpolymerization and copolymerization of olefins using a complex havingone of the formulae I a to I d.

Polymers and copolymers of olefins are of great economic importancebecause the monomers are readily available in large quantities andbecause the polymers can be varied within a wide range by variation ofthe method of preparation or the processing parameters. The catalystused is of particular significance in the process for preparing thepolymers. Apart from Ziegler-Natta catalysts, various single-sitecatalysts are of increasing importance. In the latter, central atomswhich have been examined in some detail include not only Zr as in, forexample, metallocene catalysts (H.-H. Brintzinger et al., Angew. Chem.1995, 107, 1255) but also Ni or Pd (WO 96/23010) or Fe and Co (e.g. WO98/27124). The complexes of Ni, Pd, Fe and Co are also referred to ascomplexes of late transition metals.

Metallocene catalysts have disadvantages for industrial use. The mostfrequently employed metallocenes, namely zirconocenes and hafnocenes,are sensitive to hydrolysis. In addition, most metallocenes aresensitive to many catalyst poisons such as alcohols, ethers and CO,which makes it necessary for the monomers to be carefully purified.

While Ni and Pd complexes (WO 96/23010) catalyze the formation of highlybranched polymers which are of little commercial interest, the use of Feor Co complexes leads to formation of highly linear polyethylenecontaining very low proportions of comonomer.

Furthermore, complexes by means of which ethylene can be polymerized orcopolymerized in the presence of water have been studied.

WO 98/42664 describes complexes of the formula A and closely relatedderivatives containing salicylaldimine ligands and also their use forthe polymerization of olefins.

WO 98/42665 describes complexes of the formula B and closely relatedderivatives and also their use for the polymerization of olefins. In thecomplexes of both the formula A and the formula B, the radical R on theimine nitrogen is a C₁-C₁₁-alkyl group or an ortho-substituted phenylgroup. However, their activity should be capable of improvement.

It is also known that the complexes of the formulae A and B arepolymerization-active even in the presence of small amounts of water,without the catalytic activity being adversely affected (WO 98/42664, inparticular page 17, line 14 ff; WO 98/42665, p. 16, line 13). However,these amounts of water must not exceed 100 equivalents, based on thecomplex (WO 98/42664, page 17, lines 33-35; WO 98/42665, page 16, lines30-31). However, an emulsion polymerization cannot be carried out underthese conditions. In Macromol. Symp. 2000, 150, 53, A. Tomov et al.reported that some binuclear Ni complexes are suitable as catalysts foremulsion polymerization of ethylene. However, the synthesis of thecomplexes mentioned is complicated.

WO 98/30609 discloses derivatives of A which are suitable for thepolymerization of ethylene and propylene. However, their activity is notalways satisfactory.

EP-A 0 874 005 discloses further polymerization-active complexes. Theseare preferably Ti complexes with salicylaldimine ligands. These too bearphenyl substituents or substituted phenyl substituents on the aldiminenitrogen (pages 18-23) or else the aldimine nitrogen is incorporatedinto a 6-membered ring (pages 31-32). However, they are very sensitiveto polar compounds such as water, alcohols or ethers.

In DE-A 199 61 340 it is shown that complexes of late transition metalshaving the formulae C and D

where R to R″″′ are each hydrogen, alkyl, C₇-C₁₃-aralkyl or C₆-C₁₄-aryl,and mixtures thereof are suitable for polymerizing ethylene by emulsionpolymerization. However, the activities should be capable ofimprovement. In A. Held et al., J. Chem. Soc., Chem. Commun. 2000, 301,it is shown that complexes of the formula C in which R is phenyl and R″is an SO₃—group will polymerize ethylene in an aqueous medium. Theactivity of C, too, is not yet optimal.

Owing to the great commercial importance of polyolefins, the search forvery versatile polymerization-active complexes having the highestpossible activity continues to be of great importance.

It is an object of the present invention,

-   -   to provide new complexes which are suitable for the        polymerization of olefins;    -   to provide a process for preparing the complexes of the present        invention;    -   to provide a process for the polymerization or copolymerization        of olefins using the complexes of the present invention;    -   to provide supported catalysts for the polymerization of olefins        and a process for preparing the supported catalysts of the        present invention using the complexes of the present invention;    -   to polymerize and copolymerize olefins using the supported        catalysts of the present invention;    -   to provide a process for the emulsion polymerization or        copolymerization of olefins, in particular ethylene, using the        complexes of the present invention.

We have found that this object is achieved by means of complexes havingthe structures of the formulae I a to d defined at the outset.

In the formulae I a to d, the variables are defined as follows: M is anelement of groups 6 to 10 of the Periodic Table of the Elements in theoxidation state from +2 to +4; preferably Cr, Fe, Pd or Ni, particularlypreferably Ni.

-   Nu is selected from among O, S and N—R⁷, with oxygen being    preferred;-   R¹ to R⁷ are identical or different and are selected from among    -   hydrogen,    -   C₁-C₁₈-alkyl groups, such as methyl, ethyl, n-propyl, isopropyl,        n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl,        sec-pentyl, neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl,        isohexyl, sec-hexyl, n-heptyl, isoheptyl n-octyl, n-decyl,        n-dodecyl and n-octadecyl; preferably C₁-C₁₂-alkyl such as        methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl,        sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl,        neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl, isohexyl,        sec-hexyl and n-decyl, particularly preferably C₁-C₄-alkyl such        as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl,        sec-butyl and tert-butyl;    -   examples of substituted C₁-C₁₈-alkyl groups are: monohalogenated        or polyhalogenated C₁-C₈-alkyl groups such as fluoromethyl,        difluoromethyl, trifluoromethyl, chloromethyl, dichloromethyl,        trichloromethyl, bromomethyl, dibromomethyl, tribromomethyl,        pentafluoroethyl, perfluoropropyl and perfluorobutyl,        particularly preferably fluoromethyl, difluoromethyl,        trifluoromethyl and perfluorobutyl;    -   C₂-C₁₈-alkenyl having from one to 4 isolated or conjugated        double bonds, for example vinyl, 1-allyl, 3-allyl, ω-butenyl,        ω-pentenyl, ω-hexenyl, 1-cis-buta-1,3-dienyl and        1-cis-hexa-1,5-dienyl.    -   examples of substituted C₂-C₁₈-alkenyl groups are: isopropenyl,        1-isoprenyl, α-styryl, β-styryl, 1-cis-1,2-phenylethenyl and        1-trans-1,2-phenylethenyl.    -   C₃-C₁₂-cycloalkyl such as cyclopropyl, cyclobutyl, cyclopentyl,        cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl,        cycloundecyl and cyclododecyl; preferably cyclopentyl,        cyclohexyl and cycloheptyl;    -   examples of substituted cycloalkyl groups are:        2-methylcyclopentyl, 3-methylcyclopentyl,        cis-2,4-dimethylcyclopentyl, trans-2,4-dimethylcyclopentyl,        cis-2,5-dimethylcyclopentyl, trans-2,5-dimethylcyclopentyl,        2,2,5,5-tetramethylcyclopentyl, 2-methylcyclohexyl,        3-methylcyclohexyl, 4-methylcyclohexyl,        cis-2,6-dimethylcyclohexyl, trans-2,6-dimethylcyclohexyl,        cis-2,6-diisopropylcyclohexyl, trans-2,6-diisopropylcyclohexyl,        2,2,6,6-tetramethylcyclohexyl, 2-methoxycyclopentyl,        2-methoxycyclohexyl, 3-methoxycyclopentyl, 3-methoxycyclohexyl,        2-chlorocyclopentyl, 3-chlorocyclopentyl,        2,4-dichlorocyclopentyl, 2,2,4,4-tetrachlorocyclopentyl,        2-chlorocyclohexyl, 3-chlorocyclohexyl, 4-chlorocyclohexyl,        2,5-dichlorocyclohexyl, 2,2,6,6-tetrachlorocyclohexyl,        2-thiomethylcyclopentyl, 2-thiomethylcyclohexyl,        3-thiomethylcyclopentyl, 3-thiomethylcyclohexyl and further        derivatives;    -   C₇-C₁₃-aralkyl, preferably C₇-C₁₂-phenylalkyl such as benzyl,        1-phenethyl, 2-phenethyl, 1-phenylpropyl, 2-phenylpropyl,        3-phenylpropyl, neophyl (1-methyl-1-phenylethyl), 1-phenylbutyl,        2-phenylbutyl, 3-phenylbutyl and 4-phenylbutyl, particularly        preferably benzyl;    -   C₆-C₁₄-aryl, for example phenyl, 1-naphthyl, 2-naphthyl,        1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl,        3-phenanthryl, 4-phenanthryl and 9-phenanthryl, preferably        phenyl, 1-naphthyl and 2-naphthyl, particularly preferably        phenyl;    -   C₆-C₁₄-aryl such as phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl,        2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl,        3-phenanthryl, 4-phenanthryl and 9-phenanthryl substituted by        one or more identical or different substituents selected from        among        -   C₁-C₁₈-alkyl groups such as methyl, ethyl, n-propyl,            isopropyl, h-butyl, isobutyl, sec-butyl, tert-butyl,            n-pentyl, isopentyl, sec-pentyl, neopentyl,            1,2-dimethylpropyl, isoamyl, n-hexyl, isohexyl, sec-hexyl,            n-heptyl, isoheptyl n-octyl, n-decyl, n-dodecyl and            n-octadecyl, preferably C₁-C₁₂-alkyl such as methyl, ethyl,            n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl,            tert-butyl, n-pentyl, isopentyl, sec-pentyl, neopentyl,            1,2-dimethylpropyl, isoamyl, n-hexyl, isohexyl, sec-hexyl            and n-decyl, particularly preferably C₁-C₄-alkyl such as            methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl,            sec-butyl and tert-butyl;        -   examples of substituted C₁-C₁₈-alkyl groups are:            monohalogenated or polyhalogenated C₁-C₈-alkyl groups such            as fluoromethyl, difluoromethyl, trifluoromethyl,            chloromethyl, dichloromethyl, trichloromethyl, bromomethyl,            dibromomethyl, tribromomethyl, pentafluoroethyl,            perfluoropropyl and perfluorobutyl, particularly preferably            fluoromethyl, difluoromethyl, trifluoromethyl and            perfluorobutyl;        -   C₂-C₁₈-alkenyl having from one to 4 isolated or conjugated            double bonds, for example vinyl, 1-allyl, 3-allyl,            ω-butenyl, ω-pentenyl, ω-hexenyl, 1-cis-buta-1,3-dienyl and            1-cis-hexa-1,5-dienyl.        -   examples of substituted C₂-C8-alkenyl groups are:            isopropenyl, 1-isoprenyl, α-styryl, β-styryl,            1-cis-1,2-phenylethenyl and 1-trans-1,2-phenylethenyl.        -   C₃-C₁₂-cycloalkyl such as cyclopropyl, cyclobutyl,            cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl,            cyclononyl, cyclodecyl, cycloundecyl and cyclododecyl;            preferably cyclopentyl, cyclohexyl and cycloheptyl;        -   C₇-C₁₃-aralkyl, preferably C₇-C₁₂-phenylalkyl such as            benzyl, 1-phenethyl, 2-phenethyl, 1-phenylpropyl,            2-phenylpropyl, 3-phenylpropyl, neophyl            (1-methyl-1-phenylethyl), 1-phenylbutyl, 2-phenylbutyl,            3-phenylbutyl and 4-phenylbutyl, particularly preferably            benzyl;        -   C₆-C₁₄-aryl, for example phenyl, 1-naphthyl, 2-naphthyl,            1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthryl,            2-phenanthryl, 3-phenanthryl, 4-phenanthryl and            9-phenanthryl, preferably phenyl, 1-naphthyl and 2-naphthyl,            particularly preferably phenyl;        -   halogen, for example fluorine, chlorine, bromine and iodine,            particularly preferably fluorine and chlorine;        -   C₁-C₆-alkoxy groups such as methoxy, ethoxy, n-propoxy,            isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy,            n-pentoxy, isopentoxy, n-hexoxy and isohexoxy, particularly            preferably methoxy, ethoxy, n-propoxy and n-butoxy;        -   C₆-C₁₄-aryloxy groups such as phenoxy, ortho-cresyloxy,            meta-cresyloxy, para-cresyloxy, α-naphthoxy, β-naphthoxy and            9-anthryloxy;        -   silyl groups SiR⁸R⁹R¹⁰, where R⁸ to R¹⁰ are selected            independently from among hydrogen, C₁-C₈-alkyl groups,            benzyl radicals and C₆-C₁₄-aryl groups; with preference            being given to the trimethylsilyl, triethylsilyl,            triisopropylsilyl, diethylisopropylsilyl,            dimethylhexylsilyl, tert-butyldimethylsilyl,            tert-butyldiphenylsilyl, tribenzylsilyl, triphenylsilyl and            tri-para-xylylsilyl groups and particular preference being            given to the trimethylsilyl group and the            tert-butyldimethylsilyl group;        -   silyloxy groups OSiR⁸R⁹R¹⁰, where R⁸ to R¹⁰ are selected            independently from among hydrogen, C₁-C₈-alkyl groups,            benzyl radicals and C₆-C₁₄-aryl groups; with preference            being given to the trimethylsilyloxy, triethylsilyloxy,            triisopropylsilyloxy, diethylisopropylsilyloxy,            dimethylthexylsilyloxy, tert-butyldimethylsilyloxy,            tert-butyldiphenylsilyloxy, tribenzylsilyloxy,            triphenylsilyloxy and tri-para-xylylsilyloxy groups and            particular preference being given to the trimethylsilyloxy            group and the tert-butyldimethylsilyloxy group;    -   five and six-membered nitrogen-containing heteroaryl radicals        such as N-pyrrolyl, pyrrol-2-yl, pyrrol-3-yl, N-imidazolyl,        2-imidazolyl, 4-imidazolyl, 1,2,4-triazol-3-yl,        1,2,4-triazol-4-yl, 2-pyridyl, 3-pyridyl, 4-pyridyl,        3-pyridazinyl, 4-pyridazinyl, 2-pyrimidinyl, 4-pyrimidinyl,        5-pyrimidinyl, N-indolyl and N-carbazolyl;    -   five- and six-membered nitrogen-containing heteroaryl radicals        such as N-pyrrolyl, pyrrol-2-yl, pyrrol-3-yl, N-imidazolyl,        2-imidazolyl, 4-imidazolyl, 1,2,4-triazol-3-yl,        1,2,4-triazol-4-yl, 2-pyridyl, 3-pyridyl, 4-pyridyl,        3-pyridazinyl, 4-pyridazinyl, 2-pyrimidinyl, 4-pyrimidinyl,        5-pyrimidinyl, N-indolyl and N-carbazolyl substituted by one or        more identical or different substituents selected from among        -   C₁-C₁₈-alkyl groups such as methyl, ethyl, n-propyl,            isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl,            n-pentyl, isopentyl, sec-pentyl, neopentyl,            1,2-dimethylpropyl, isoamyl, n-hexyl, isohexyl, sec-hexyl,            n-heptyl, isoheptyl n-octyl, n-decyl, n-dodecyl and            n-octadecyl, preferably C₁-C₁₂-alkyl such as methyl, ethyl,            n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl,            tert-butyl, n-pentyl, isopentyl, sec-pentyl, neopentyl,            1,2-dimethylpropyl, isoamyl, n-hexyl, isohexyl, sec-hexyl            and n-decyl, particularly preferably C₁-C₄-alkyl such as            methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl,            sec-butyl and tert-butyl;        -   examples of substituted C₁-C₁₈-alkyl groups are:            monohalogenated or polyhalogenated C₁-C₈-alkyl groups such            as fluoromethyl, difluoromethyl, trifluoromethyl,            chloromethyl, dichloromethyl, trichloromethyl, bromomethyl,            dibromomethyl, tribromomethyl, pentafluoroethyl,            perfluoropropyl and perfluorobutyl, particularly preferably            fluoromethyl, difluoromethyl, trifluoromethyl and            perfluorobutyl;        -   C₂-C₁₈-alkenyl having from one to 4 isolated or conjugated            double bonds, for example vinyl, 1-allyl, 3-allyl,            ω-butenyl, ω-pentenyl, ω-hexenyl, 1-cis-buta-1,3-dienyl and            1-cis-hexa-1,5-dienyl.        -   examples of substituted C₂-C₈-alkenyl groups are:            isopropenyl, 1-isoprenyl, α-styryl, β-styryl,            1-cis-1,2-phenylethenyl and 1-trans-1,2-phenylethenyl.        -   C₃-C₁₂-cycloalkyl such as cyclopropyl, cyclobutyl,            cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl,            cyclononyl, cyclodecyl, cycloundecyl and cyclododecyl;            preferably cyclopentyl, cyclohexyl and cycloheptyl;        -   C₇-C₁₃-aralkyl, preferably C₇-C₁₂-phenylalkyl such as            benzyl, 1-phenethyl, 2-phenethyl, 1-phenylpropyl,            2-phenylpropyl, 3-phenylpropyl, neophyl            (1-methyl-1-phenylethyl), 1-phenylbutyl, 2-phenylbutyl,            3-phenylbutyl and 4-phenylbutyl, particularly preferably            benzyl;        -   C₆-C₁₄-aryl, for example phenyl, 1-naphthyl, 2-naphthyl,            1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthryl,            2-phenanthryl, 3-phenanthryl, 4-phenanthryl and            9-phenanthryl, preferably phenyl, 1-naphthyl and 2-naphthyl,            particularly preferably phenyl;        -   halogen, for example fluorine, chlorine, bromine and iodine,            particularly preferably fluorine and chlorine;        -   C₁-C₆-alkoxy groups such as methoxy, ethoxy, n-propoxy,            isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy,            n-pentoxy, isopentoxy, n-hexoxy and isohexoxy, particularly            preferably methoxy, ethoxy, n-propoxy and n-butoxy;        -   C₆-C₁₄-aryloxy groups such as phenoxy, ortho-cresyloxy,            meta-cresyloxy, para-cresyloxy, α-naphthoxy, β-naphthoxy and            9-anthryloxy;        -   silyl groups SiR⁸R⁹R¹⁰, where R⁸ to R¹⁰ are selected            independently from among hydrogen, C₁-C₈-alkyl groups,            benzyl radicals and C₆-C₁₄-aryl groups; with preference            being given to the trimethylsilyl, triethylsilyl,            triisopropylsilyl, diethylisopropylsilyl,            dimethylhexylsilyl, tert-butyldimethylsilyl,            tert-butyldiphenylsilyl, tribenzylsilyl, triphenylsilyl and            tri-para-xylylsilyl groups and particular preference being            given to the trimethylsilyl group and the            tert-butyldimethylsilyl group;        -   silyloxy groups OSiR⁸R⁹R¹⁰, where R⁸ to R¹⁰ are selected            independently from among hydrogen, C₁-C₈-alkyl groups,            benzyl radicals and C₆-C₁₄-aryl groups; with preference            being given to the trimethylsilyloxy, triethylsilyloxy,            triisopropylsilyloxy, diethylisopropylsilyloxy,            dimethylthexylsilyloxy, tert-butyldimethylsilyloxy,            tert-butyldiphenylsilyloxy, tribenzylsilyloxy,            triphenylsilyloxy and tri-para-xylylsilyloxy groups and            particular preference being given to the trimethylsilyloxy            group and the tert-butyldimethylsilyloxy group.

In a particular embodiment, adjacent radicals R¹ to R⁷ may be joined toone another to form a 5- to 12-membered ring. For example, R¹ and R⁶ maytogether be: —(CH₂)₃—(trimethylene), —(CH₂)₄—(tetramethylene),—(CH₂)₅—(pentamethylene), —(CH₂)₆—(hexamethylene), —CH₂—CH═CH—,—CH₂—CH═CH—CH₂—, —CH═CH—CH═CH—, —O—CH₂—O—, —O—CHMe—O—, —O—CH—(C₆H₅)—O—,—O—CH₂—CH₂—O—, —NMe—CH₂—CH₂—NMe—, —NMe—CH₂—NMe— or —O—SiMe₂—O— whereMe═CH₃. In a preferred example, R¹ and R⁶ together form a1,3-butadiene-1,4-diyl unit which may in turn be monosubstituted orpolysubstituted by C₁-C₈-alkyl. In a further preferred example R² and R⁴together form a 1,3-butadien-1,4-diyl unit which may in turn bemonosubstituted or polysubstituted by C₁-C₈-alkyl.

-   L¹ is selected from among uncharged, inorganic and organic ligands,    for example phosphines of the formula (R¹¹)_(x)PH_(3−x) or amines of    the formula (R¹¹)_(x)NH_(3−x), where x is an integer from 0 to 3.    However, ethers (R¹¹)₂O such as dialkyl ethers, e.g. diethyl ethers,    or cyclic ethers, e.g. tetrahydrofuran, H₂O, alcohols (R¹¹)OH such    as methanol or ethanol, pyridine, pyridine derivatives of the    formula C₅H_(5−x)(R¹³)_(x)N, for example 2-picoline, 3-picoline,    4-picoline, 2,3-lutidine, 2,4-lutidine, 2,5-lutidine, 2,6-lutidine    or 3,5-lutidine, CO, C₁-C₁₂-alkylnitriles or C₆-C₁₄-arylnitriles,    e.g. acetonitrile, propionitrile, butyronitrile or benzonitrile, are    also suitable. It is also possible to use singly or multiply    ethylenically unsaturated double bond systems such as ethenyl,    propenyl, cis-2-butenyl, trans-2-butenyl, cyclohexenyl or    norbornenyl as ligand.-   L² is selected from among inorganic and organic anionic ligands, for    example from among    -   halide ions such as fluoride, chloride, bromide and iodide,        preferably chloride and bromide,    -   amide anions (R¹¹)_(x−1)NH_(2−x), where x is an integer from 0        to 3,    -   C₁-C₆-alkyl anions such as (CH₃)—, (C₂H₅)—, (C₃H₇)—, (n-C₄H₉)—,        (tert-C₄H₉)— and (C₆H₁₄)—;    -   allyl anions and methallyl anions,    -   benzyl anions and    -   aryl anions such as (C₆H₅)—.-   z is an integer from 1 to 3, e.g. 0, 1, 2 or 3;-   R¹ are identical or different and are selected from among hydrogen,    -   C₁-C₈-alkyl groups,    -   benzyl radicals and    -   C₆-C₁₄-aryl groups, where these groups are as defined above and        where 2 radicals R¹¹ may be covalently bound to one another.

In a particular embodiment, L¹ and L² are joined to one another by oneor more covalent bonds. Examples for such ligands are1,5-cyclooctadienyl ligands (“COD”), 1,6-cyclodecenyl ligands and1,5,9-all-trans-cyclododecatrienyl ligands.

In a further particular embodiment, L¹ is tetramethylethylenediamine,with only one nitrogen coordinating to the nickel.

The novel complexes of the formulae I a to d are generally prepared fromligands of the formula II a or II b, in which the variables are asdefined above. To synthesize the complexes of the present invention, theligands are firstly deprotonated by means of a base and subsequentlyreacted with metal compounds of the formula MX₂, MX₃, MX₄ or ML¹L².

Bases which can be used are the metal alkyls customary in organometallicchemistry, for example methyllithium, ethyllithium, n-butyllithium,sec-butyllithium, tert-butyllithium or hexyllithium, also Grignardcompounds such as ethylmagnesium bromide, also lithium amide, sodiumamide, potassium amide, potassium hydride or lithium diisopropylamide(“LDA”). Solvents which have been found to be useful are high-boilingsolvents such as toluene, ortho-xylene, meta-xylene, para-xylene,ethylbenzene or mixtures of these, also acyclic or cyclic ethers such as1,2-dimethoxyethane, tetrahydrofuran or diethyl ether.

This deprotonation is generally complete after a few hours; it isappropriate to employ a reaction time of from 2 to 10 hours, preferablyfrom 3 to 5 hours. The temperature conditions are generally notcritical; temperatures of from −90° C. to −20° C. are preferred for thedeprotonation.

The deprotonated ligand and the metal compound of the formula MX₂, MX₃,MX₄ or ML¹L² are subsequently reacted with one another.

X are identical or different and are selected from among: halogen suchas fluorine, chlorine, bromine and iodine, preferably chlorine andbromine;

-   -   C₁-C₈-alkyl groups such as methyl, ethyl, n-propyl, isopropyl,        n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl,        sec-pentyl, neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl,        isohexyl, sec-hexyl, n-heptyl, isoheptyl and n-octyl; preferably        C₁-C₆-alkyl such as methyl, ethyl, n-propyl, isopropyl, n-butyl,        isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl,        sec-pentyl, neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl,        isohexyl, sec-hexyl, particularly preferably C₁-C₄-alkyl such as        methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl        and tert-butyl;    -   C₃-C₁₂-cycloalkyl such as cyclopropyl, cyclobutyl, cyclopentyl,        cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl,        cycloundecyl and cyclododecyl; preferably cyclopentyl,        cyclohexyl and cycloheptyl;    -   C₇-C₁₃-aralkyl, preferably C₇-C₁₂-phenylalkyl such as benzyl,        1-phenethyl, 2-phenethyl, 1-phenylpropyl, 2-phenylpropyl,        3-phenylpropyl, neophyl (1-methyl-1-phenylethyl), 1-phenylbutyl,        2-phenylbutyl, 3-phenylbutyl and 4-phenylbutyl, particularly        preferably benzyl;    -   C₆-C₁₄-aryl, for example phenyl, 1-naphthyl, 2-naphthyl,        1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl,        3-phenanthryl, 4-phenanthryl and 9-phenanthryl, preferably        phenyl, 1-naphthyl and 2-naphthyl, particularly preferably        phenyl;        X are preferably identical.

MX₂, MX₃, MX₄ or ML¹L² can optionally be stabilized by unchargedligands. Possible uncharged ligands are the customary ligands ofcoordination chemistry, for example cyclic and acyclic ethers, amines,diamines, nitriles, isonitriles or phosphines. Particular preference isgiven to diethyl ether, tetrahydrofuran, 1,2-dimethoxyethane,tetramethylethylenediamine, acetonitrile or triphenylphosphine.Particularly in cases in which, for example, Ni-dialkyl compounds are tobe used, uncharged ligands have been found to be useful. The unchargedligands can also be used as solvents.

The conditions for the reaction are not critical per se; it is usual tomix the deprotonated ligand II and MX₂, MX₃, MX₄ and ML¹L² with oneanother in a suitable solvent such as benzene, toluene, ethylbenzene,ortho-xylene, meta-xylene or para-xylene, chlorobenzene, cyclohexane,acetonitrile, tetrahydrofuran, methylene chloride or a mixture of these.The temperature can be in the range from −100° C. to +150° C.,preferably from −78° C. to +100° C. It is important that the reaction iscarried out in the absence of oxygen and moisture.

The molar ratio of ligand to M can be in the range from 5:1 to 1:5.However, since the ligands of the formula II are more difficult toobtain than the metal compounds, molar ratios of ligand: M in the rangefrom 1:1 to 1:3 are preferred. Particular preference is given tostoichiometric amounts.

The novel complexes of the formulae I a to d can be purified by themethods customary in organometallic chemistry, with particularpreference being given to crystallization. Filtration via filter aidssuch as Celite® is also useful.

For the polymerization, it is not necessary in all cases to isolate thecomplexes of the present invention. It is also possible to react aligand of the formula II with a suitable metal compound of the formulaMX₂, MX₃, MX₄ or ML¹L² only immediately prior to the polymerization andgenerate the complex in situ.

If X in the metal compound of the formula MX₂, MX₃ or MX₄ is selectedfrom the group consisting of C₁-C₈-alkyl groups, C₃-C₁₂-cycloalkylgroups, C₇-C₁₃-aralkyl groups and C₆-C₁₄-aryl groups, the deprotonationof the ligand of the formula II can be omitted. In these cases, it hasbeen found to be preferable not to isolate the complexes of the presentinvention but instead to generate them in situ only immediately prior tothe polymerization.

The preparation of the ligands of the formula II a and II b is describedin the parallel patent applications DE-A 10107045 and DE-A 10107043.They can be obtained by reacting a deprotonated imine or nitrile havingan acidic a-H atom with an electrophilic compound of the formula III

where the variables are as defined above.

It has been found that the novel complexes of the formulae I a to I dare suitable for polymerizing olefins. They are particularly useful forpolymerizing and copolymerizing ethylene and propylene to form highmolecular weight polymers.

For the novel complexes of the formulae I a to d to be catalyticallyactive, they have to be activated. Suitable activators are selectedaluminum and boron compounds bearing electron-withdrawing radicals (e.g.trispentafluorophenylborane, trispentafluorophenylaluminum,N,N-dimethylanilinium tetrakispentafluorophenylborate,tri-n-butylammonium tetrakispentafluorophenylborate,N,N-dimethylanilinium tetrakis(3,5-bisperfluoromethyl)phenylborate,tri-n-butylammonium tetrakis(3,5-bisperfluoromethyl)phenylborate andtritylium tetrakispentafluorophenylborate). Preference is given todimethylanilinium tetrakispentafluorophenylborate, trityliumtetrakispentafluorophenylborate and trispentafluorophenylboran.

If boron or aluminum compounds are used as activators for the novelcomplexes of the formulae I a to d, they are generally used in a molarratio of from 1:10 to 10:1, based on M; they are preferably used in aratio of from 1:2 to 5:1 and particularly preferably in stoichiometricamounts.

Another suitable class of activators are aluminoxanes.

The structure of the aluminoxanes is not known precisely. They areproducts which are obtained by careful partial hydrolysis of aluminumalkyls (cf. DE-A 30 07 725). These products are not in the form of purechemical compounds, but are mixtures of open-chain and cyclic structuresof the types IV a and IV b. These mixtures are presumably in dynamicequilibrium.

In the formulae IV a and IV b the radicals R^(m) are each

-   -   C₁-C₁₂-alkyl such as methyl, ethyl, n-propyl, isopropyl,        n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl,        sec-pentyl, neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl,        isohexyl, sec-hexyl, n-heptyl, isoheptyl, n-octyl, n-nonyl,        n-decyl or n-dodecyl, preferably C₁-C₆-alkyl such as methyl,        ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl,        tert-butyl, n-pentyl, isopentyl, sec-pentyl, neopentyl,        1,2-dimethylpropyl, isoamyl, n-hexyl, isohexyl, sec-hexyl,        particularly preferably methyl;    -   C₃-C₁₂-cycloalkyl such as cyclopropyl, cyclobutyl, cyclopentyl,        cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl,        cycloundecyl or cyclododecyl, preferably cyclopentyl, cyclohexyl        or cycloheptyl;    -   C₇-C₂₀-aralkyl, preferably C₇-C₁₂-phenylalkyl such as benzyl,        1-phenethyl, 2-phenethyl, 1-phenylpropyl, 2-phenylpropyl,        3-phenylpropyl, 1-phenylbutyl, 2-phenylbutyl, 3-phenylbutyl or        4-phenylbutyl, particularly preferably benzyl, or    -   C₆-C₁₄-aryl such as phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl,        2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl,        3-phenanthryl, 4-phenanthryl or 9-phenanthryl, preferably        phenyl, 1-naphthyl or 2-naphthyl, particularly preferably        phenyl; and

-   n is an integer from 0 to 40, preferably from 1 to 25 and    particularly preferably from 2 to 22.

Cage-like structures for aluminoxanes are also discussed in theliterature (Y. Koide, S. G. Bott, A. R. Barron Organometallics 1996, 15,2213-26; A. R. Barron Macromol. Symp. 1995, 97, 15-25). Regardless ofthe actual structure of the aluminoxanes, they are suitable asactivators for the novel metal complexes of the formula I.

Mixtures of various aluminoxanes are particularly preferred activatorsin cases when the polymerization is carried out in a solution in aparaffin, for example n-heptane or isododecane. A particularly preferredmixture is the CoMAO available commercially from Witco GmbH, which hasthe formula [(CH₃)_(0.9)(iso-C₄H₉)_(0.1)AlO]_(n).

To activate the complexes of the formulae I a to d by means ofaluminoxanes, an excess of aluminoxane, based on M, is generallynecessary. Appropriate molar ratios of M:Al are in the range from 1:10to 1:10 000, preferably from 1:50 to 1:1000 and particularly preferablyfrom 1:100 to 1:500.

It is generally believed that activators for metal complexes of theformulae I a to d abstract a ligand L¹ or L². Instead of aluminum alkylcompounds of the formula III a or III b or the above-described aluminumor boron compounds having electron-withdrawing radicals, the activatorcan also be, for example, an olefin complex of rhodium or nickel.

Preferred nickel-(olefin)_(y)-complexes, where y=1, 2, 3 or 4, availablecommercially from Aldrich are Ni(C₂H₄)₃, Ni(1,5-cyclooctadiene)₂“Ni(COD)₂”, Ni(1,6-cyclodecadiene)₂ orNi(1,5,9-all-trans-cyclododecatriene)₂. Particular preference is givento Ni(COD)₂.

Particularly useful activators of this type are mixedethylene/1,3-dicarbonyl complexes of rhodium, for exampleethylenerhodium acetylacetonate Rh(acac)(CH₂═CH₂)₂, ethylenerhodiumbenzoylacetonate Rh(C₆H₅—CO—CH—CO—CH₃) (CH₂═CH₂)₂ orRh(C₆H₅—CO—CH—CO—C₆H₅)(CH₂═CH₂)₂. Rh(acac)(CH₂═CH₂)₂ is suitable. Thiscompound can be synthesized by the method of R. Cramer in Inorg. Synth.1974, 15, 14.

Some of the complexes of the formula I can be activated by ethylene. Theease of the activation reaction depends critically on the nature of theligand L¹.

Depending on the synthesis conditions, the complexes of the presentinvention can be obtained as monomers or else as dimers which arebridged via two of the substituents L². The activation does not dependcritically on whether the complexes are in monomeric or dimeric form.

The chosen complex of the formula I and the activator together form acatalyst system.

The activity of the catalyst system of the invention can be increased byaddition of further aluminum alkyl of the formula Al(R^(m))₃ oraluminoxanes, particularly when compounds of the formula IV a or IV b orthe abovementioned aluminum or boron compounds havingelectron-withdrawing radicals are used as activators; aluminum alkyls ofthe formula Al(R^(m))₃ or aluminoxanes can also act as molar massregulators. A further effective molar mass regulator is hydrogen. Themolar mass can be regulated particularly effectively via the reactiontemperature and the pressure. If a boron compound as described above isto be used, the addition of an aluminum alkyl of the formula Al(R^(m))₃is particularly preferred.

It has been found that the novel complexes of the formulae I a to d aresuitable for polymerizing olefins. They are particularly useful forpolymerizing and copolymerizing ethylene and propylene.

Pressure and temperature conditions during the polymerization can bechosen within wide limits. Pressures in a range from 0.5 bar to 4000 barhave been found to be useful; preference is given to from 10 to 75 baror high-pressure conditions of from 500 to 2500 bar. A suitabletemperature range has been found to be from 0 to 120° C., preferablyfrom 40 to 100° C. and particularly preferably from 50 to 85° C.

As monomers, mention may be made of the following olefins: ethylene,propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene and1-undecene, with propylene and ethylene being preferred and ethylenebeing particularly preferred.

Suitable comonomers are a-olefins, for example from 0.1 to 20 mol % of1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene or1-undecene. Further suitable comonomers are isobutene and styrene, alsointernal olefins such as cyclopentene, cyclohexene, norbornene andnorbornadiene.

Solvents which have been found to be suitable are toluene, ortho-xylene,meta-xylene, para-xylene and ethylbenzene and also mixtures of these,such as diethyl ether, tetrahydrofuran, chlorobenzene,1,3-dichlorobenzene, dichloromethane and also, under high-pressureconditions, supercritical ethylene.

Hydrogen has been found to be an effective chain transfer agent inpolymerizations using the novel complexes of the formula I, i.e. themolecular weight of the polymers obtainable by means of the catalystsystem of the present invention can be reduced by addition of hydrogen.If sufficient hydrogen is added, waxes are obtained. The hydrogenconcentration required for this depends, inter alia, on the type ofpolymerization plant employed.

For the catalyst systems of the present invention to be able to be usedin modern polymerization processes such as suspension processes, bulkpolymerization processes or gas-phase processes, they have to beimmobilized on a solid support. Otherwise, morphology problems with thepolymer (lumps, deposits on walls, blockages in lines or heatexchangers) can occur and force shutdown of the plant. Such animmobilized catalyst system will be referred to as a catalyst.

It has been found that the catalyst systems of the present invention canbe readily deposited on solid support materials. Suitable supportmaterials are, for example, porous metal oxides of metals of groups 2 to14 or mixtures thereof, also sheet silicates and zeolites. Preferredexamples of metal oxides of groups 2 to 14 are SiO₂, B₂O₃, Al₂O₃, MgO,CaO and ZnO. Preferred sheet silicates are montmorillonites andbentonites; the preferred zeolite is MCM-41.

Particularly preferred support materials are spherical silica gels andaluminosilicate gels of the formula SiO₂. a Al₂O₃, where a is generallyfrom 0 to 2, preferably from 0 to 0.5. Such silica gels are commerciallyavailable, e.g. Silica Gel SG 332, Sylopol® 948 or 952 or S 2101 from W.R. Grace or ES 70X from Crosfield.

As regards the particle size of the support material, mean particlediameters which have been found to be useful are from 1 to 300 μm,preferably from 20 to 80 μm, determined by known methods such as sievemethods. The pore volume of these supports is from 1.0 to 3.0 ml/g,preferably from 1.6 to 2.2 ml/g and particularly preferably from 1.7 to1.9 ml/g. The BET surface area is from 200 to 750 m²/g, preferably from250 to 400 m²/g.

To remove impurities, in particular moisture, adhering to the supportmaterial, the support materials can be baked before doping, withtemperatures of from 45 to 1000° C. being suitable. Temperatures of from100 to 750° C. are particularly useful for silica gels and other metaloxides. This baking can be carried out for from 0.5 to 24 hours,preferably from 1 to 12 hours. The pressure conditions depend on theprocess chosen; baking can be carried out in a fixed-bed process, astirred vessel or else in a fluidized-bed process. Baking can in generalbe carried out at atmospheric pressure. However, reduced pressures offrom 0.1 to 500 mbar are advantageous, a range from 1 to 100 mbar isparticularly advantageous and a range from 2 to 20 mbar is veryparticularly advantageous. In the case of fluidized-bed processes, onthe other hand, it is advisable to employ a slightly superatmosphericpressure in a range from 1.01 bar to 5 bar, preferably from 1.1 to 1.5bar.

Chemical treatment of the support material with an alkyl compound suchas an aluminum alkyl, a lithium alkyl or an aluminoxane is likewisepossible.

In the case of a suspension polymerization process, use is made ofsuspension media in which the desired polymer is insoluble or soluble toonly a slight extent, because otherwise deposits of product occur in theparts of the plant in which the product is separated off from thesuspension medium and force repeated shutdowns and cleaning operations.Suitable suspension media are saturated hydrocarbons such as propane,n-butane, isobutane, n-pentane, isopentane, n-hexane, isohexane andcyclohexane, with isobutane being preferred.

Pressure and temperature conditions during the polymerization can bechosen within wide limits. A suitable pressure range has been found tobe from 0.5 bar to 150 bar, preferably from 10 to 75 bar. A suitabletemperature range has been found to be from 0 to 120° C., preferablyfrom 40 to 100° C.

As monomers, mention may be made of the following olefins: ethylene,propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene and1-undecene, with preference being given to ethylene.

Suitable comonomers are α-olefins, for example from 0.1 to 20 mol % of1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene or1-undecene. Further suitable comonomers are isobutene and styrene, alsointernal olefins such as cyclopentene, cyclohexene, norbornene andnorbornadiene.

Furthermore, hydrogen has been found to be an effective chain transferagent in polymerizations using the catalysts of the present invention,i.e. the molecular weight of the polymers obtainable by means of thecatalysts of the present invention can be reduced by addition ofhydrogen. If sufficient hydrogen is added, waxes are obtained. Thehydrogen concentration required for this depends, inter alia, on thetype of polymerization plant employed. Addition of hydrogen increasesthe activity of the catalysts of the present invention.

The catalysts of the present invention can also be used together withone or more other polymerization catalysts known per se. Thus, they canbe used together with

-   -   Ziegler-Natta catalysts,    -   supported metallocene catalysts containing transition metals of        groups 4 to 6 of the Periodic Table of the Elements,    -   catalysts based on late transition metals (WO 96/23010),    -   Fe or Co complexes with pyridyldiimine ligands, as are disclosed        in WO 98/27124,    -   or chromium oxide catalysts of the Phillips type.

If a plurality of catalysts is used, it is possible to mix variouscatalysts with one another and to meter them in together or to usecosupported complexes on a common support or else to meter variouscatalysts separately into the polymerization vessel at the same point orat various points.

It has also been found that the novel complexes of the formulae I a andI b, in particular those in which M=Ni, are particularly suitable forthe polymerization or copolymerization of 1-olefins, preferablyethylene, in emulsion polymerization processes.

Apart from other 1-olefins as comonomers, for example propene, 1-butene,1-hexene, 1-octene or 1-decene, the catalyst system of the presentinvention also enables polar comonomers to be incorporated, with from0.1 to 50 mol % of comonomer being able to be used. Preference is givento

-   -   acrylates such as acrylic acid, methyl acrylate, ethyl acrylate,        2-ethylhexyl acrylate, n-butyl acrylate or tert-butyl acrylate;    -   methacrylic acid, methyl methacrylate, ethyl methacrylate,        n-butyl methacrylate or tert-butyl methacrylate;    -   vinyl carboxylates, particularly preferably vinyl acetate,    -   unsaturated dicarboxylic acids, particularly preferably maleic        acid,    -   unsaturated dicarboxylic acid derivatives, particularly        preferably maleic anhydride and alkylimides of maleic acid, e.g.        N-methylmaleimide.

Furthermore, it is possible to prepare terpolymers comprising at least 2of the abovementioned monomers together with ethylene.

The emulsion polymerization of the 1-olefins using the novel metalcomplexes of the formula I can be carried out in a manner known per se.

The order of addition of the reagents in the emulsion polymerization isnot critical. Thus, the solvent can firstly be pressurized with gaseousmonomer or liquid monomer can be metered in, after which the catalystsystem is added. However, the solution of the catalyst system can alsofirstly be diluted with further solvent, after which monomer is added.

The actual polymerization usually proceeds at a minimum pressure of 1bar; below this pressure, the polymerization rate is too low. Preferenceis given to 2 bar and particular preference is given to a minimumpressure of 10 bar.

The maximum practical pressure is 4000 bar; at higher pressures, thedemands made on the material of construction of the polymerizationreactor are very high and the process becomes uneconomical. Preferenceis given to 100 bar and particular preference is given to 50 bar.

The polymerization temperature can be varied within a wide range. Theminimum practical temperature is 10° C., since the polymerization ratedecreases at low temperatures. Preference is given to a minimumtemperature of 40° C., particularly preferably 65° C. The temperatureshould not exceed 350° C. and is preferably not above 150° C.,particularly preferably not above 100° C.

Prior to the polymerization, the complex of the formulae I a to d isdissolved in an organic solvent or in water. The solution is stirred orshaken for a number of minutes to ensure that it is clear. The stirringtime can be, depending on the solubility of the compound concerned, from1 to 100 minutes.

At the same time, any activator necessary is dissolved in a secondportion of the same solvent or else in acetone.

Suitable organic solvents are aromatic solvents such as benzene,toluene, ethylbenzene, ortho-xylene, meta-xylene and para-xylene andalso mixtures thereof. Further suitable solvents are cyclic ethers suchas tetrahydrofuran and dioxane or acyclic ethers such as diethyl ether,di-n-butyl ether, diisopropyl ether or 1,2-dimethoxyethane. Ketones suchas acetone, methyl ethyl ketone or diisobutyl ketone are also suitable,and the same applies to amides such as dimethylformamide ordimethylacetamide. It is also possible to use mixtures of these solventswith one another and mixtures of these solvents with water or alcoholssuch as methanol or ethanol.

Preference is given to acetone and water and mixtures of acetone andwater in any mixing ratio. The amount of solvent is likewise notcritical, but it has to be ensured that the complex and the activatorcan dissolve completely, otherwise a decrease in the activity has to beexpected. The dissolution process can, if desired, be accelerated byultrasonic treatment.

Any emulsifier which is optionally added can be dissolved in a thirdportion of the solvent or else together with the complex.

The amount of emulsifier is selected so that the mass ratio of monomerto emulsifier is greater than 1, preferably greater than 10 andparticularly preferably greater than 20. The less emulsifier used, thebetter. The activity in the polymerization is significantly increased ifan emulsifier is added. This emulsifier can be nonionic or ionic innature.

Nonionic emulsifiers which can be used are, for example, ethoxylatedmonoalkylphenols, dialkylphenols and trialkylphenols (EO content: 3-50,alkyl radical: C_(4-C) ₁₂) and ethoxylated fatty alcohols (EO content:3-80; alkyl radical: C₈-C₃₆). Examples are the Lutensol® grades fromBASF AG or the Triton® grades from Union Carbide.

Customary anionic emulsifiers are, for example, alkali metal andammonium salts of alkyl sulfates (alkyl radical: C₈-C₁₂), of sulfuricmonoesters of ethoxylated alkanols (EO content: 4-30, alkyl radical:C₁₂-C₁₈) and ethoxylated alkylphenols (EO content: 3-50, alkyl radical:C₄-C₁₂), of alkylsulfonic acids (alkyl radical: C₁₂-C₁₈) and ofalkylarylsulfonic acid (alkyl radical: C₉-C₁₈).

Suitable cationic emulsifiers are generally primary, secondary, tertiaryor quaternary ammonium salts, alkanolammonium salts, pyridinium salts,imidazolinium salts, oxazolinium salts, morpholinium salts, thiazoliniumsalts and also salts of amine oxides, quinolinium salts, isoquinoliniumsalts, tropylium salts, sulfonium salts and phosphonium salts, in eachcase containing a C₆-C₁₈-alkyl, -aralkyl or heterocyclic radical.Examples which may be mentioned are dodecylammonium acetate or thecorresponding hydrochloride, the chlorides or acetates of the various2-(N,N,N-trimethylammonium)ethyl esters of paraffinic acids,N-cetylpyridinium chloride, N-laurylpyridinium sulfate and alsoN-cetyl-N,N,N-trimethylammonium bromide,N-dodecyl-N,N,N-trimethylammonium bromide,N,N-distearyl-N,N-dimethylammonium chloride and also the geminisurfactant N,N′-(lauryldimethyl)ethylenediamine dibromide. Numerousfurther examples may be found in H. Stache, Tensid-Taschenbuch,Carl-Hanser-verlag, Munich, Vienna, 1981 and in McCutcheon's,Emulsifiers & Detergents, MC Publishing Company, Glen Rock, 1989.

The components, namely complex in solution, optionally the solution ofthe emulsifier and optionally the solution of the activator, aresubsequently introduced into the polymerization reactor. Polymerizationreactors which have been found to be useful are stirred vessels andautoclaves and also tube reactors, with the tube reactors being able tobe configured as loop reactors.

The monomer or monomers to be polymerized is/are mixed with thepolymerization medium. As polymerization medium, it is possible to usewater or mixtures of water with the above-mentioned solvents. It shouldbe ensured that the proportion of water is at least 50% by volume, basedon the total mixture, preferably at least 90% by volume and particularlypreferably at least 95% by volume.

The solutions of the complex, if used the activator and if used theemulsifier are combined with the mixture of monomer and aqueouspolymerization medium. The order of addition of the various componentsis not critical per se. However, it is necessary for the components tobe combined sufficiently quickly for no crystallization of any sparinglysoluble complexes formed as intermediates to occur.

The process of the present invention gives polyolefins and olefincopolymers in high yields, i.e. the activity of the complexes of thepresent invention under the conditions of emulsion polymerization isvery high.

As polymerization process, continuous and batchwise processes aresuitable in principle. Preference is given to semicontinuous processes(semibatch processes) in which all components are mixed and then furthermonomer or monomer mixture is metered in during the polymerization.

The process of the present invention firstly gives aqueous polymerdispersions.

The mean particle diameter of the polymer particles in the dispersionsobtained according to the present invention is from 10 to 1000 nm,preferably from 50 to 500 nm and particularly preferably from 70 to 350nm. The distribution of the particle diameters can be very uniform, butdoes not have to be. For some applications, in particular for those inwhich high solids contents (>55%) are present, broad or bimodaldistributions are even preferred.

The polymers obtained by the process of the present invention haveindustrially interesting properties. In the case of polyethylene, theyhave a high degree of crystallinity, which can be shown by, for example,the number of branches. Less than 100 branches, preferably less than 50branches, per 1000 carbon atoms of the polymer, determined by ¹H-NMR and¹³C-NMR spectroscopy, are found.

The enthalpies of fusion of the polyethylenes obtainable by the processof the present invention are greater than 100 J/g, preferably greaterthan 140 and particularly preferably greater than 180 J/g, measured byDSC.

The molecular weight distributions of the polyethylenes obtainable bythe process of the present invention are narrow, i.e. the Q values arein the range from 1.1 to 3.5, preferably from 1.5 to 3.1.

Advantages of the dispersions obtained according to the presentinvention are firstly their low price owing to the cheap monomers andprocess and, secondly, that they are more stable to weathering than aredispersions of polybutadiene or butadiene copolymers. Compared todispersions of polymers comprising acrylates or methacrylates as mainmonomer, the lower tendency to undergo saponification is advantageous. Afurther advantage is that most olefins are volatile and unpolymerizedresidual monomers can easily be removed. A final advantage is that nomolar mass regulators such as tert-dodecyl mercaptan which are, firstly,difficult to separate off and, secondly, have an unpleasant odor have tobe added during the polymerization.

The polymer particles can be obtained as such by removal of the waterand, if necessary, the organic solvent or solvents from the aqueousdispersions obtained initially. Numerous customary methods are availablefor removal of the water and, if necessary, the organic solvent orsolvents, for example filtration, spray drying or evaporation. Thepolymers obtained in this way have a good morphology and a high bulkdensity.

The particle sizes can be determined by light scattering methods. Areview may be found in D. Distler “WäBrige Polymerdispersionen”,Wiley-VCH Verlag, 1st edition, 1999, Chapter 4.

The dispersions obtained according to the present invention can be usedadvantageously in numerous applications, for example paper applicationssuch as paper coating or surface sizing, also paints and varnishes,building chemicals, adhesives raw materials, molded foams, textile andleather applications, coatings on the reverse side of carpets,mattresses or pharmaceutical applications.

The following example illustrates the invention.

General Preliminary Remarks:

All work was carried out in the absence of air and moisture usingstandard Schlenk techniques. Apparatus and chemicals were preparedaccordingly. The polymer viscosity was determin d in accordance with ISO1628-3. The molar masses were determined by means of GPC. For the GPCmeasurements, the following conditions based on DIN 55672 were selected:solvent: 1,2,4-trichlorobenzene, flow: 1 ml/min, temperature: 140° C.,calibration: PE standards, instrument: Waters 150C. The number of methylgroups was determined by IR spectroscopy.

Synthesis of the Imine III.1:

The starting materials, viz. 4.97 g of acetophenone

(41.4 mmol) and 7.33 g of 2,6-diisopropylaniline (41.4 mmol), wereplaced in a 250 ml round-bottomed flask fitted with a water separator,dissolved in 70 ml of toluene and, after addition of 500 mg ofp-toluenesulfonic acid, refluxed for 2 hours. The orange solution waswashed twice with H₂O and then once with 10% strength NaHCO₃ solutionuntil neutral. The organic phase was dried over Na₂SO₄. After thesolvent had been taken off on a rotary evaporator, traces of toluene andalso unreacted amine and ketone were taken off in a high vacuum at105-115° C. The oily imine crystallized overnight.

This method was used to prepare: imine III.1

Yield: 84.6%, empirical formula: C₂₀H₂₅N, color: yellow, m.p.: 68-69° C.

1H NMR (CDCl₃): 1.21 (12H, m, 4×CH₃), 2.16 (3H, s, CH₃), 2.83 (2H,sept., CH), 7.11-8.12 (8H, m, phenyl)

13C NMR (CDCl₃): 18.0, 22.9, 23.2, 28.2, 122.9, 123.3, 127.1, 128.4,130.3, 136.0, 139.1, 146.7, 164.7 (C═N)

IR (KBr, cm⁻¹): 3056 (w), 2958 (m), 2867 (m), 1630 (s), 1578 (s), 1449(s), 1366 (m), 1289 (s), 1243 (m), 1192 (m), 1111 (w), 1044 (w), 1027(m), 969 (w), 938 (m), 822 (m), 774 (vs), 760 (vs), 735 (s), 693 (vs)

M⁺=279.2 m/e

Synthesis of the Ligand II.1

0.18 ml of diisopropylamine (1.3 mmol) was placed in a baked-out Schlenktube which had been flushed with argon, dissolved in 10 ml of THF(absolute) and admixed at −80° C. with n-BuLi (0.72 ml, 1.1 equivalents,2.0 M solution in pentane). After removal of the cold bath (EtOH, N₂),the resulting LDA solution was stirred for ½ h at room temperature.

The imine III.1 (0.36 g, 1.30 mmol) was added to the freshly preparedLDA solution at −80° C. After removal of the cold bath, the dissolvedstarting material was stirred at room temperature for 2 hours andthereby deprotonated (color change: yellowish to yellow-green).

0.24 g of benzophenone (1.3 mmol) were subsequently added at roomtemperature and the mixture was stirred overnight.

The yellow THF solution was then poured into 100 ml of ice water andextracted three times with 25 ml each time of diethyl ether. Thecombined organic phases were washed with H₂O, dried over Na₂SO₄ and theorganic solvents were removed on a rotary evaporator. The yellow productcrystallized over a period of 2 hours. Subsequent recrystallization fromethyl acetate/hexane gave the pure β-hydroxyimine II.1.

Ligand II.1

Yield: 72%, empirical formula: C₃₃H₃₅NO, color: whitish yellow, m.p.:121-122° C.

1H NMR (CDCl₃): 0.61 (6H, d, 2×CH₃), 0.82 (6H, d, 2×CH₃), 2.19 (2H,sept, CH), 3.76 (2H, s, CH₂), 6.80-7.51 (19H, m, phenyl, OH)

13C NMR (CDCl₃): 22.0, 24.5, 27.9 (CH₃, CH), 48.4 (CH₂), 78.5 (C—OH),122.9, 124.2, 126.0, 126.7, 127.0, 128.1, 128.2, 128.3, 129.5, 130.0,132.4, 136.8, 137.6, 143.6, 147.4 (phenyl), 170.4 (C═N)

IR (KBr, cm⁻¹): 3288 (m, broad), 3062 (w), 2962 (m), 2925 (w), 2867 (m),1634 (vs), 1492 (m), 1453 (vs), 1343 (m), 1227 (m), 1065 (m), 1042 (s),1015 (s), 942 (s), 917 (m), 899 (s), 805 (m), 749 (vs), 700 (vs), 637(s) M⁺=461.3 m/e

Polymerization:

46 mg (0.1 mmol) of ligand II.1 and 40 mg (0.22 mmol) of (CH₃)₂Ni(TMEDA)were added to 250 ml of toluene in a 1l steel autoclave and were mixedby stirring. The autoclave was subsequently pressurized with 40 bar ofethylene and polymerization was carried out at 70° C. for 120 minutes.This gave 3.3 g of polyethylene, which corresponds to an activity of 7.5kg of polyethylene/mol of Ni.h.

TMEDA: Tetramethylethylenediamine.

1. A complex having one of the formulae I a to d,

where the variables are defined as follows: M is an element of groups 6to 10 of the Periodic Table of the Elements in the oxidation state +2 to+4; Nu is selected from the group consisting of O, S and N—R⁷; R¹ to R⁷to are selected from among hydrogen, C₁-C₁₈-alkyl, substituted orunsubstituted, C₂-C₁₈-alkenyl, substituted or unsubstituted, having fromone to 4 isolated or conjugated double bonds; C₃-C₁₂-cycloalkyl,substituted or unsubstituted, C₇-C₁₃-aralkyl, C₆-C₁₄-aryl, unsubstitutedor substituted by one or more identical or different substituentsselected from the group consisting of C₁-C₈-alkyl, substituted orunsubstituted, C₃-C₁₂-cycloalkyl, C₇-C₁₃-aralkyl, C₆-C₁₄-aryl, halogen,C₁-C₆-alkoxy, substituted or unsubstituted, C₆-C₁₄-aryloxy, SiR⁸R⁹R¹⁰and O—SiR⁸R⁹R¹⁰; five- and six-membered nitrogen-containing heteroarylradicals, unsubstituted or substituted by one or more identical ordifferent substituents selected from the group consisting ofC₁-C₈-alkyl, substituted or unsubstituted, C₃-C₁₂-cycloalkyl,C₇-C₁₃-aralkyl, C₆-C₁₄-aryl, halogen, C₁-C₆-alkoxy, C₆-C₁₄-aryloxy,SiR⁸R⁹R¹⁰ and O—SiR⁸R⁹R¹⁰; where adjacent radicals R¹ to R⁷ may bejoined to one another to form a 5- to 12-membered non-aromatic ring; L¹is an uncharged, organic or inorganic ligand, L² is an organic orinorganic anionic ligand, where L¹ and L² may be joined to one anotherby one or more covalent bonds, z is an integer from 1 to 3, R⁸ to R¹⁰are identical or different and are selected from the group consisting ofhydrogen, C₁-C₈-alkyl, C₃-C₁₂-cycloalkyl, C₇-C₁₃-aralkyl andC₆-C₁₄-aryl.
 2. The complex as claimed in claim 1, wherein M is selectedfrom the group consisting of nickel and palladium.
 3. The complex asclaimed in claim 1, wherein L¹ is selected from the group consisting ofphosphines (R¹¹)_(x)PH_(3-x), amines (R¹¹)_(x)NH_(3-x), ethers (R¹¹)₂O,H₂O, alcohols (R¹¹)OH, pyridine, pyridine derivatives of the formulaC₅H_(5-x)(R¹¹)_(x)N, CO, C₁-C₁₂-alkylnitriles, C₆-C₁₄-arylnitriles andethylenically unsaturated double bond systems, where x is an integerfrom 0 to 3; L² is selected from the group consisting of halide ions,amide ions (R¹¹)_(x-1)NH_(2-x), C₁-C₆-alkyl anions, allyl anions, benzylanions and aryl anions; the radicals R¹¹ are identical or different andare selected from the group consisting of hydrogen, C₁-C₈-alkyl,C₃-C₁₂-cycloalkyl, C₇-C₁₃-aralkyl and C₆-C₁₄-aryl.
 4. A process forpreparing the complex as claimed in claim 1, which comprises firstlydeprotonating a ligand of the formula II a or II b

with a base and subsequently reacting the product with from 0.2 to 5equivalents of a metal compound MX₄, MX₃, ML¹L² or MX₂, where X ishalogen, C₁-C₈-alkyl, C₃-C₁₂-cycloalkyl, C₇-C₁₃-arallcyl or C₆-C₁₄-aryland where MX₂, MX₃ or MX₄ may optionally be stabilized by furtheruncharged ligands.
 5. A process for the polymerization orcopolymerzation of olefins comprising polymerizing one or more olefinmonomers in the presence of the complex of claim
 1. 6. A process forpreparing a supported catalyst for the polymerization orcopolymerization of olefins, which comprises depositing one or morecomplexes as claimed in claim 1, and optionally an activator, on a solidsupport.
 7. A supported catalyst for the polymerization orcopolymerization of olefins which is prepared as set forth in claim 6.8. A process for the polymerization or copolymerization of olefinscomprising polymerizing one or more olefin monomers in the presence ofthe supported catalyst as claimed in claim
 7. 9. A process for theemulsion polymerization or copolymerization of ethylene or other1-olefins and optionally further olefins comprising polymerizingethylene or other 1-olefins and optionally further olefins in thepresence of the complex as claimed in claim 1.